1. Field of the Invention
The present invention relates to an apparatus and method for selecting a Quality of Service (QoS) in a portable communication system. More particularly, the present invention relates to an apparatus and method for a user of a portable terminal to directly select a Quality of Service (QoS) and use a video telephone service.
2. Description of the Related Art
In recent years, wireless communications technologies have evolved to provide supplementary functions, such as data communication functions, in addition to conventional voice communication functions. Exemplary data communication functions include General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA) Evolution-Data Optimized (EV-DO), CDMA Evolution-Data and Voice (EV-DV), Wideband Code Division Multiple Access (WCDMA) and High-Speed Downlink Packet Access (HSDPA). As a result of the development of data communication functions, a video telephone service is better able to be provided.
The video telephone service requires a caller identifying and signaling means. An exemplary signaling means is a Session Initiation Protocol (SIP).
SIP is an application-layer signaling protocol that specifies a procedure for identifying and locating portable terminals on the Internet and for creating or deleting and modifying multimedia communication sessions between the portable terminals. SIP is based on a request/response control paradigm for creating, modifying, and terminating multimedia service sessions such as Internet conferencing, voice communication, voice mail, event notification and instant messaging. SIP can be used for at least one of Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).
FIG. 1 is a diagram illustrating a conventional portable communication system providing a video communication service.
In FIG. 1, the portable communication system can include an origination portable terminal 100, a video communication server 110, and a destination portable terminal 102. Herein, the portable communication system may further be operable with another H.324M compatible device 114 via a gateway 112.
The portable terminals 100 and 102 supporting the video communication service communicate with each other in compliance with an H.324M protocol using a Circuit Service Data (CSD) channel when performing the video communication service.
The H.324M protocol is a protocol utilized for video communication that is suitable for use with a low bandwidth communications path. That is, the H.324M protocol is used to transmit image data using only a bandwidth of 42 Kbps to 48 Kbps from a total bandwidth of 64 Kbps and uses the remaining bandwidth for a data channel for a voice signal.
In the event that the portable terminals 100 and/or 102 are able to communicate with another H.324M compatible device 114, the portable terminals 100 and/or 102 will not be able to use the video communication service until a communications path is established via the video communication server 110 and gateway 112.
Therefore, there is a drawback that upon initiation of a video communication service over the CSD channel in the portable communication system, a video communication service cannot be provided with a high quality of service because of limited bandwidth.
Also, there is a drawback in that use of the video communication service is limited because the video communication service over the CSD channel can only be provided between users registered to a specific communication service provider.
Thus, there is needed an apparatus and method for providing a high quality video communication service in a portable communication system.